//
//  ViewController.swift
//  test
//
//  Created by Arvin on 2017/5/23.
//  Copyright © 2017年 Arvin. All rights reserved.
//

import UIKit

class ViewController: UIViewController {

    override func viewDidLoad() {
        super.viewDidLoad()
        
        var labelstr=""
        labelstr="字符串声明"
        if labelstr.isEmpty {
            print("空字符串")
        }
        
        
    }
}

